Illuminator.



PATENTED JUNE 19, 1906.

0. A. MYGATT.

ILLUMINATOR.

APPLIUATION FILED MAY 20, 1904- 2 SHBETS-SHEBT l.

PATENTBD JUNE 19, 1906.

0. A. MYGATT. ILLUMINATOR.

APPLICATION FILED MAY 20. 1904.

2 SHEETS-SHEET 2.

FIG.13.

PI G- 9.

TIC+.J.0.

@ INVENTOR I is .with light-difiusing ribs or prisms.

'. sideis preferably smooth.

UNITED "STATES Toall whom it may concern: I 7 Be it known that I, O'rrsA. MYGATT, a citizen of the United States, residing at New cleaning thesame.

will render the I I the eye and to reduce to a minimum the disadvantagesof prismaticlass construction,

York, in the county of New York and State of New York, have invented.certain new and useful Im rovements in Illuminators, of

which the ollowing is azspecification. v

' This invention relates "to prismatic illuminators' or compositeartificial lights, shades, and reflectors. v The object of the inventionis to so combine with an artificial light (generally an incandescentelectric'or a glow lamp) a suitable diffusing-shade, globe, or cover anda prise matic reflector as to dgive 'a good distribution of lightaccomplanie with such diffusion as 'ght harmless or agreeable to duetothe accumulation o dust on rismatic shades and reflectors and theculty of My invention: consists in certain mechan- I i'cal constructionswhereby combinations may be effected and in the combination of;

the various parts, so that efiective results may be obtained,substantially as hereinafter stated and claimed.

coveror shade ofglasshaving1 opening for dust entrance. '1 e said coveror shade is substantially covered- 1 The outscribed exists when a;glow-lam having an 'ran ed above said cover.

A simple embodiment of the present invention-would-be'- .First, 'acommon incandescent lam I Secondly, surrounding the lamp al iffusiveinterior of Thirdly, a prismatic-glass{reflector having 'reflectingrismson its upper surface, the

lowers ace being preferably'-smooth,' ar

- -T e's'ame combination'as'that above deinclosing casing is substitutedor the-commonincandescent electric lamp; but a noninclosed arc-lightwould be a substantially" 1 different element in the combination.

Some modifications of this central idea are I hereinafter'describedto'show its wide range 5' I of adaptability. p v Figure 1 is a sectionof, a reflector-and lamp-cover as applied to a glow-hght. Fig. 2. is asection of same online 2 2. Fig. 3 s a Specification of Letters Patent.Application filed May 20,1904. .Seria1No.2l )6,831-. I

Patented'June 19, 1906.

broken section or diagram of reflector, showng course of-somelight-rays. .Fig. 4 is a broken section of lamp shade or cover, showingcourse'of some light-rays. Fig." 5'is an elevation of reflector and lam-cover of different contour with a-lamp-ho der. -Fi 6' is a modificationshowing a prismatic re ector resting on the lamp shade orcover, the lampbeing omitted for convenience. Fig. 7 is a 'paitlal elevation andpartial section of a modification showing the inside of the shadecovered with flutings. Fig. 85 is a partly broken section of a shadehaving risms.

Fig. 9 is a section ofa fluted piece wit light rays passing in onedirection and indicating light diffusion; .Fig. 10 isa similar view withlight-rays passing ina reverse direction.

Flg. 1-1 is a section showingpne form of support for reflector andshade; and Fig. 12 indicates another form, the difiusing-ribs andreflecting-prisms not appearing, owing to the small scale of thefigures. Fig. 13 is a brokento iIplanof the reflector H", F1g'.. 6..

y- Design Patents Nos. 32,685 and 32,686, of May 22, 1900, I show anddescribe very eflicient prismatic-glass reflectors." The presentinvention proposes to combine with such or an equivalentprismatic-glassreflector and with a lam or light an intermediate k in the light.

, order that my meaning may be fully understoed, Iwill here define someof the terms I shall employ in this specification.= By

light diflusion I mean that light-rays from a lam ;l passing through astructure of" glass ereby' broken up, softened," and are t lamp cover orsha ewhich is little liable to accumulate dust on the outer surface andwhich has the-property of diflusing or soften- '8 5 sprayed out, with noparticular regard to di-.'

rection. By distribution of light I mean that light-rays, either byreflection or refraction, or both, are directed in a-givenand'predetermined direction. In the present inven- .'tionthedistributionof light is effected'by a prismatic reflector; the diffusionby'a shade or cover. 'By a rism I mean a projection from the main-b0 ofthe shade or reflector integral with said body and having at least twoplane faces and one outer angle, but sometimes having more than twoplane faces and more than one outer-angle, as the atent of Blondel,hereinafter referred to. y a

from within, strike one mate term.-

[cumference than general double reflecting prism I mean aprism in whichmany of the light-rays enter the glass of the outer faces of the prismat about forty-five degrees thereto, are reflected across the body ofthe prism at about ninety degrees from the first direction, encounterthe second face at about forty-five degrees, and are again reflected toemerge from the reflector at the side of entry. (See Fig. 3.) Byvertical prisms I mean such asextend in length outward and downward fromthe top or center, widening and thickening to retain the favorableangle. On a flat reflector these risms are bounded byra- 'al lines; on aspl ferical reflector by meridi onal lines. Vertical is only an ap roxi-By flutings I mean suc projections as have no extended plane faces, butmerge in curves,as in Figs. 9 and 10. Such fl'utings may difiuse, but donot distribute, light. Flutings may be either vertical orcircumfer'ential. I

The direction of light distribution by a prismatic reflector isdetermined not only by the form of the prisms, but by the'f'orm' of thereflector-bod on which th prisms are arrange-d. It will readily beunderstood that a reflector, curved as in Fig. 1, will direct the lightreflected downwardly into a smaller irouldf a comparatively flatreflector, as in Fig. '6. v

The present invention is intended for use 3 with the reflector above thelight and its shade or cover. While the illuminator may be inclined tosome extent, protection from dust is sacrificed in considerable degreeif it is so inclined that the shade or cover Projects beyond aperpendicular line from the edge of the reflector.

Patent to Synnott, N 0. 641,166, J anugjiiy 9,'19'O0, illustrates a lobewith interior -fusing-ribs and outsi e bulls-eye's. This I4, 1896,describes a is not a pri matic reflector, although it diffuses light. iv i Patent to Blondelet 112., No. 563,83'6,July globe in one piece ofplummeting efficiency and providing 0t 01' diffusion and distribution oflight;

' but this is likely to gather dust and when covtween the reflector andthe lamp.

e'r'ed with dust losesits efficiency. I In my Patent No. 705,426, ofJuly 26, 1902,

I use a rismatic reflector in combination with a co o'r'ed-glassstructure inter osed be- This does light-rays as my not give suchdiflusion of here are no diffusing present invention.

My present invention, in which a ribbed or light softening or diffusingdiffusive shade or cover and prismatic reflector are combined, difiusionand distribulightas does the Blondei device referred to and is nearlyfree from deterioration by accumulation of dust.

- body. The

not be great.

through th mouth 'or bottom In Fig. 1, A represents a glow-lamp, aconvenient form of electric light in a closed casing, to which my lampcover and reflector may be applied. A shade or light softening ordiffusing lamp-cover B is applied to this lamp A, so as to surround thesame. This cover B is smooth externally and in the form shownin Fi 1 hasa generally cylindrical ower end of this shade or cover is preferablyopen, as at B, to permit the entrance of air for cooling. -A neck orcollar 0 furnishes a support for the shade by means of metallic cap orring D, attached to the lampsocket and having hooks E, which turn inunder the edge of the collar. The cover B is made of glass, referablytransparent. It is pressed in a mo d to form vertical or longitudinalprisms F on the interior surface. The lower end of the cover ispreferably drawn in after the article is. pressed and while stillplastic as is common in formin lass articles. T e outer surface issmooth, argely to prevent the adhesion of dust and to permit the passageof light-rays without obstruction and without much change of direction.The prisms are preferably quite small, so that the thickness of coverBand its prisms may The function of prisms F is to s lit up and diffusethe light-re s assing through said shade or cover. ig t-ra from lamp A,striking these prisms, general y at obtuse or acute angles, are brokenup and divided. The lines a b b,.Fi 4, indicate in a en'eialwa whattakes p ace with some light-rays. almost any art of the surface coveredb risms F, Wil pass through the glass, but wi l e broken up and dividedas it emer es, the

subdivided rays being more or less iverted from their originaldirection, according to the angle at which the rays encounter the planefaces of the prisms. Thus few rays can pass e cover B without beingdivided or diverted, While very few rays will be reflected back,to'wardthe light by the prisms F. The upper part of the shade or coverB is closed by the support D, so there is little chance for the entry ofdust into the interior of the shade B. 'As the prisms are substantiallyvertical, an" dust enterin at the open l3 will find iitt e chance forlod ment.

b'l he reflector H is of pressed glass, prefera ly transparent, and issmooth on the interior, and is externally covered with prisms I,preferab of a character which are adapted to rod'uce the maximumreflection, as (in re erred form) double-refieotin prisms. b" 5 indicatelight-rays as reflecte The subra bis or may be similarly ot or prism inthe direction I).

It has been found in practice that dust accumulating on the up er sideof pr smatlcglass reflectors of the c aracter d'escr1be'd has reflectedby an- I shown, as it is suppose little or no eflect on the reflectedrays, A

large accumulation of dust will of course prevent the transmission oflight through the reflector, which light under normal conditions .mayamount to as much as fifteen to thirty I per cent. of the light reachingthe inner f of the reflector. I

In Fig. 1 the reflector H is shown as resting on a shoulder of the shadeor cover B. In Fig. 5 no means of supporting reflector is i to besupported in an' usual or convenient manner. n Fi 6 the lam shade orcover B is represente as covere with internal-diflusionprismoidsarranged in the form of diamonds,

and the relatively flat reflector H is covered on its uppersurfacewithprismoids in the.

formof diamonds. In Fig. 7. the shade or 'le utings will accumulate moredust than an actually'smooth surface, the dust can be very easilyremoved from'a fluted surface,

' sembled with the shade B held by a metallic" clasp K, and support aflange on t of the reflector ma thus aiding in the iflusion of the;light, ,but -not 1n the distribution thereof.

which is not the case with a prismatic reflector., The reflector H -has'1ts uppe'r outer.

surface covered with prisms of the character described in myapplication, Serial No,

= 199,721, filed March 24, 1904.

. construction of the shade or cover and reflecs.

Figs; 11 and 12 showdifferent forms of tor, so that as in Fig.- 11 thepartsmay be asor other clasp K, and when so suspended said shade forms asupport for the reflector H,

or in Fig. .12 the reflector H mayl be heldfby cover Bi 1 Instead ofmaking theinterior of the shade or cover quite smooth this may befluted, as-

in Fig- 7, and in some cases the interior face be fluted, the flutingsThe various forms of light-diffusing covers B B B &c., havebeendescrlbed as covered wlth mternal surfaces, in some cases prlsms,

in others 'prismoids, ,in others flutings, in I others ribs.

The object of these various surfaces is the. diffusion of light andnotthe reflection of light. I For want of a better term cover B is repre-'sented as externally covered. as to its u per part with circumferentialflutings.

I. have used the .word ribs in the claims as including the genus to'which any of the dein a closed glass casing, of a light-diffusing shadehaving internal ribs and surrounding saidcasing, and a glass reflectorsurmounting said shade, and having reflecting-prisms on its uppersurfaces. 1

,3. he combination withan electric light in a closed'glass casing, of alight-.diflusing shade surrounding said casing at a little distance andhaving internal ribsand a partly-' smooth exterior, .and a lassreflector surmounting said shade andaving external reflecting-prisms. ps

v 4. The combination with a closedelectric havmg internal vertica ribsand being smooth on itsouter lower portion, and a glass reflec- 2 lamp,ofa surroundin light-diffusing shade torv resting on saidshade andhaving external reflecting-prisms.

5. The combination with an electric light in a closed glass casing. of ashade a little re-' moved therefrom but of a generally similar form, andhaving'internal diffusing-ribs and being smooth on the lower exteriorpart of 1ts ingsaid shade, and havin external reflecting-ribs and asmooth interior surface.

5 outer surface, and a glass reflectorsurmounte 6. The combination withan electric light in a closed glass casing, of a glass shade, open atthe bottom and closed. at the top, surf rounding said casing, .andhaving internal light-diffusing bodies and a artly-smooth exterior, anda superposed re ector of glass '95 halving reflecting-prisms on itsupper surface 0 Iii testimony-whereof'I affix my signature in-presenceof two witnesses. OTIS A. MYGATT. I Witnesses: 1 I

THEOPHILUS PARsoNs, HOWARD TAYLOR.

